The present invention is directed toward medical devices which minimize the risk of infection by inhibiting the entry, adherence, and/or proliferation of microbes.
Whenever a medical device comes in contact with a patient, a risk of infection is created. Thus, a contaminated examination glove, tongue depressor, or stethoscope could transmit infection. The risk of infection dramatically increases for invasive medical devices, such as intravenous catheters, arterial grafts, intrathecal or intracerebral shunts, which not only are, themselves, in intimate contact with body tissues and fluids, but also create a portal of entry for pathogens. A number of methods for reducing the risk of infection have been developed, none of which have been clinically proven to be completely satisfactory.
U.S. Pat. No. 3,566,874, issued Mar. 2, 1971, by Shepherd et al. discloses the coating of catheters, especially urinary catheters, with hydrophilic acrylate and methacrylate polymer, which are, themselves, said to be associated with antimicrobial activity. Shepherd et al. indicates that their antiinfective activity may be enhanced by incorporating antibiotic into the polymer coating. The soaking of polymer-coated catheters in aqueous solutions of antibiotics is disclosed.
U.S. Pat. No. 4,612,337, issued Sep. 16, 1986, by Fox, Jr. et al., teaches soaking a polymeric material with a solution of an antimicrobial agent dissolved in an organic solvent, soaking the polymeric material with an organic solvent for a metal salt, and resoaking the polymeric material with the solution of the antimicrobial in organic solvent. Acetic acid, chloroform, ethanol, acetone and ether are disclosed as suitable organic solvents.
U.S. Pat. No. 4,925,668, issued May 15, 1990, by Khan et al. discloses a substantially hydrophilic polymeric medical article having a coating of chlorhexidine and a silicone on its surface, and may have chlorhexidine bulk distributed throughout the article. Solutions of chlorhexidine and silicone oil in ethanol-Freon TF are disclosed.
U.S. Pat. No. 5,013,717, issued May 7, 1991, by Solomon et al. discloses medical articles coated with silicone and antithrombotic agent, using solvent systems such as toluene, petroleum ether, methylene chloride or fluorinated hydrocarbons, which may further comprise polar solvents such as ethanol or isopropanol.
U.S. Pat. No. 5,013,306, issued May 7, 1991, by Solomon et al., relates to polymeric medical articles steeped in a solution of chlorhexidine (preferably 5-15%) in water, methylene chloride or methanol.
U.S. Pat. No. 5,019,096, issued May 28, 1991, by Fox, Jr. et al., teaches the coating of medical articles with solutions of polymer and antiinfective agent to form a layer of polymer containing antiinfective agent on the surface of the article. Suitable solvents include acetic acid, methyl acetate, ethyl acetate, hexane, N-N-dimethylacetamide, tetrahydrofuran, alcohols, water, N-ethyl-2-pyrrolidone, n-cyclohexyl-2-pyrrolidone and mixtures thereof.
Certain devices have incorporated antiinfective agents in proximity to portals of entry.
U.S. Pat. No. 4,432,766, issued Feb. 21, 1984, and U.S. Pat. No. 4,738,668, issued Apr. 19, 1988, both by Bellotti et al., disclose a pair of separate conduits, each having an internal seal zone. The ends of the conduits may be joined, antiseptic (e.g. chlorine gas) may be instilled, and then the internal seals may be opened to permit fluid flow.
U.S. Pat. No. 4,623,329, issued Nov. 18, 1986, by Drobish et al., discloses a concentric, replenishable fluid antimicrobial agent reservoir about the shaft or drainage tube of a catheter.
Segura et al., 1989, J. Clin. Microbiol. 27: 2656-2659 discloses an intravascular catheter having a hub comprising an antiseptic chamber containing a solution of antiinfective agent, such as 3% iodinated alcohol.
Messing et al., 1990, Clinical Nutrition 9: 220-225 discloses the injection of antibiotic solution into an intravenous catheter, and retaining that solution for 12 hours per day, as a way of diminishing catheter-related sepsis in patients receiving parenteral nutrition.
U.S. Pat. No. 5,176,665, issued Jan. 5, 1993, by Watanabe et al. discloses a device which may be passed into a urine collecting container, and through which antiinfective agent may be introduced into the container. The device eliminates or prevents the proliferation of pathogens in the container.
U.S. Pat. No. 5,236,422, issued Aug. 17, 1993, by Eplett et al., discloses a cylindrical antiseptic cuff with an inner shaft to be placed along a urinary catheter within a patient's distal urethra. In alternative embodiments, the cuff may be charged with antimicrobial agent (e.g. antibiotic fluid), or may be constructed of concentric layers of material which may be successively removed once colonized with bacteria.
U.S. Pat. No. 5,263,930, issued Nov. 23, 1993, by Ensminger, discloses an implantable patient access port which provides a percutaneous route for access using an external filament such as an external catheter, needle, wire or optical fiber. The access port incorporates an internal reservoir for the retention of an antibacterial fluid and further includes a means for refilling the fluid chamber.
In contrast to the medical articles disclosed in the prior art, the present invention relates to an improved method of impregnating an article surface with antiinfective agent, and provides antiinfective activity in hubs and ports without the use of instilled fluids or gases.